1689-71-0Relevant articles and documents
Porphyrins and Azaporphines as Catalysts in Alkene Epoxidations with Peracetic Acid.
Banfi, Stafano,Montanari, Fernando,Quici, Silvio,Barkanova, Svetlana. V.,Kaliya, Oleg L.,et al.
, p. 2317 - 2320 (1995)
The reactivities of five MnIII(Cl) - phorphinoids were compared in the catalytic alkene epoxidations in CH3CN solution with peracetic acid as primary oxidant.Porphyrins 1 and 2 bearing Cl and NO2 substituents showed the best efficiency while te
Iron-Catalyzed Enantioselective Epoxidations with Various Oxidants: Evidence for Different Active Species and Epoxidation Mechanisms
Zima, Alexandra M.,Lyakin, Oleg Y.,Ottenbacher, Roman V.,Bryliakov, Konstantin P.,Talsi, Evgenii P.
, p. 60 - 69 (2017)
Iron complexes with chiral bipyrrolidine-derived aminopyridine (PDP) ligands are among the most efficient Fe-based bioinspired catalysts for regio- and stereoselective oxidation of C-H and C=C moieties with hydrogen peroxide. Besides hydrogen peroxide, other oxidants (peroxycarboxylic acids and organic hydroperoxides) can be effectively used. In this work, we have examined the mechanistic landscape of the Fe(PDP) catalyst family with various oxidants: H2O2, organic hydroperoxides, and peracids. The combined EPR spectroscopic, enantioselectivity, Hammett, Z-stilbene epoxidation stereoselectivity, and 18O-labeling data witness that the same oxoiron complexes [(L)FeV=O(OC(O)R)]2+ are the actual epoxidizing species in both the catalyst systems (L)Fe/H2O2/carboxylic acid and (L)Fe/AlkylOOH/carboxylic acid. On the contrary, in the systems (L)Fe/R2C(O)OOH (R2 = CH3 or 3-Cl-C6H4), in the presence or in the absence of carboxylic acid, the epoxidation is predominantly conducted by the acylperoxo-iron(III) intermediates [(L)FeIII(OOC(O)R2)]2+, in a concerted fashion.
Mn(III)-Iodosylarene Porphyrins as an Active Oxidant in Oxidation Reactions: Synthesis, Characterization, and Reactivity Studies
Guo, Mian,Lee, Yong-Min,Seo, Mi Sook,Kwon, Yong-Ju,Li, Xiao-Xi,Ohta, Takehiro,Kim, Won-Suk,Sarangi, Ritimukta,Fukuzumi, Shunichi,Nam, Wonwoo
, p. 10232 - 10240 (2018)
Mn(III)-iodosylarene porphyrin adducts, [Mn(III)(ArIO)(Porp)]+, were synthesized by reacting electron-deficient Mn(III) porphyrin complexes with iodosylarene (ArIO) at -60 °C and characterized using various spectroscopic methods. The [Mn(III)(ArIO)(Porp)]+ species were then investigated in the epoxidation of olefins under stoichiometric conditions. In the epoxidation of olefins by the Mn(III)-iodosylarene porphyrin species, epoxide was formed as the sole product with high chemoselectivities and stereoselectivities. For example, cyclohexene oxide was formed exclusively with trace amounts of allylic oxidation products; cis- and trans-stilbenes were oxidized to the corresponding cis- and trans-stilbene oxides, respectively. In the catalytic epoxidation of cyclohexene by an electron-deficient Mn(III) porphyrin complex and sPhIO at low temperature (e.g., -60 °C), the Mn(III)-iodosylarene porphyrin species was evidenced as the active oxidant that effects the olefin epoxidation to give epoxide as the product. However, at high temperature (e.g., 0 °C) or in the case of using an electron-rich manganese(III) porphyrin catalyst, allylic oxidation products, along with cyclohexene oxide, were yielded, indicating that the active oxidant(s) was not the Mn(III)-iodosylarene adduct but probably high-valent Mn-oxo species in the catalytic reactions. We also report the conversion of the Mn(III)-iodosylarene porphyrins to high-valent Mn-oxo porphyrins under various conditions, such as at high temperature, with electron-rich porphyrin ligand, and in the presence of base (OH-). The present study reports the first example of spectroscopically well-characterized Mn(III)-iodosylarene porphyrin species being an active oxidant in the stoichiometric and catalytic oxidation reactions. Other aspects, such as one oxidant versus multiple oxidants debate, also were discussed.
Grafted metallocalixarenes as single-site surface organometallic catalysts
Notestein, Justin M.,Iglesia, Enrique,Katz, Alexander
, p. 16478 - 16486 (2004)
Metallocalixarenes were grafted onto silica using a surface organometallic approach and shown to be active and selective catalysts for epoxidation of alkenes using organic hydroperoxides. Calixarene-TiIV precursors were anchored at surface dens
The role of solvent friction in an orbital symmetry controlled reaction: Ring closure of a carbonyl ylide to cis-2,3-diphenyloxirane
Lipson, Matthew,Peters, Kevin S.
, p. 1691 - 1696 (1998)
The dynamics of the orbital symmetry controlled ring closure of the trans-ylide, formed upon the 266 nm photolysis of trans-2,3-diphenyloxirane, to produce cis-2,3-diphenyloxirane is examined in a variety of n-alkane solvents as a function of temperature. An unsuccessful attempt was made to model the kinetics within the theoretical framework developed by Kramers for a one-dimensional reaction coordinate. A model developed by Grote and Hynes that employs a frequency-dependent friction was found to give a significantly better fit to the experimental data. The possibility that a multidimensional reaction coordinate is necessary to describe the reaction dynamics is discussed.
EPOXIDATION REACTIONS CATALYZED BY IRON PORPHYRINS. OXYGEN TRANSFER FROM IODOSYLBENZENE.
Groves,Nemo
, p. 5786 - 5791 (1983)
The epoxidation of olefins by iodosylbenzene is catalyzed by synthetic iron porphyrins. With (chloro-5, 10, 15, 20 -tetraphenylporphyrinato) iron(III) (FeTPPCl), cyclohexadiene oxide was produced in 93% yield and with (chloro-5, 10, 15, 20-tetra-o-tolyporphyrinato) iron (III) (FeTTPCl), cycloctene oxide was produced in 84% yield. Cis olefins were found to be more reactive than trans olefins. Thus, whereas cis-stilbene was epoxidized by FeTPPCl/iodosylbenzene in 77% yield, trans-stilbene was unreactive under these conditions. The degree of cis/trans selectivity was a sensitive function of substitution of the porphyrin periphery. With (chloro-5, 10, 15, 20-tetramesitylporphyrinato)iron(III), the relative reactivity of cis-and trans-cyclododecene was 8. 92:1. Similarly, the less reactive cis double bond of trans, trans, cis-cyclododecatriene could be selectively epoxidized by this catalyst. Trans 1,2-disubstituted double bonds showed similar reactivities. These results suggest an approach of the double bond from the side of iron-bound oxygen and parallel to the prophyrin plane. A mechanism involving formation of an oxygen transfer from a reactive iron-oxo intermediate is proposed for this reaction.
A novel and efficient catalytic epoxidation of olefins with adducts derived from methyltrioxorhenium and chiral aliphatic amines
Vezzosi, Stefano,Guimerais Ferre, Anna,Crucianelli, Marcello,Crestini, Claudia,Saladino, Raffaele
, p. 262 - 269 (2008)
Nitrogen-based adducts derived from methyltrioxorhenium(VII) and chiral aliphatic amines have been synthesized and applied to the efficient catalytic epoxidation of olefins with urea hydrogen peroxide complex as the primary oxidant. These complexes retain their catalytic activity when microencapsulated in polystyrene. A moderate steroinduction was obtained in the epoxidation of prochiral olefins with complexes between methyltrioxorhenium and chiral trans-1,2-cyclohexyldiamine. The values of steroinduction were found to increase after the microencapsulation process.
Picosecond Photochemistry of 2,3-Diphenyloxyranes: Reaction from a Vibrationally Unrelaxed Electronic Excited State
Manring, Lewis E.,Peters, Kevin S.
, p. 8077 - 8079 (1984)
Picosecond photochemistry of trans-1,2-diphenyloxirane (Ia) and cis-1,2-diphenyloxirane (Ib) is studied in cyclohexane and acetonitrile after 266-nm excitation by a 25-ps laser pulse.Carbonyl ylides, IIa and IIb, are formed by disrotatory opening of the s
Asymmetric Epoxidation of Unfunctionalized Olefins Using Novel Chiral Dihydroisoquinolinium Salts as Organocatalysts
Ali, K. Ben
, p. 638 - 646 (2021/06/02)
Abstract: Two new non-racemic chiral dihydroisoquinolinium salts with N-substituents bulkier than a methyl group have been synthesized from (1S,2R)-norephedrine. These salts were used to catalyze asymmetric epoxidation of a series of prochiral olefins. One of the two new catalysts provided higher enantioselectivities (up to 66% ee) than the reference salt containing an N-methyl substituent.
Modification of MnFe2O4 surface by Mo (VI) pyridylimine complex as an efficient nanocatalyst for (ep)oxidation of alkenes and sulfides
Bouzari, Narges,Bezaatpour, Abolfazl,Babaei, Behnam,Amiri, Mandana,Boukherroub, Rabah,Szunerits, Sabine
, (2021/03/04)
In this current paper, we report a new type of heterogeneous molybdenum (+6) complex, prepared by covalent grafting of cis-dioxo?molybdenum (VI) pyridylimine complex on the surface of MnFe2O4 nanoparticles (NP) and characterized using various physicochemical techniques. The recyclable prepared nanocatalyst was tested for sulfoxidation of sulfides and epoxidation of alkenes under solvent-free condition. The catalyst exhibited high turnover frequency for the oxidization of cyclooctene and cyclohexene (10,850 h?1) and thioanisole and dimethyl sulfide (41,250 h?1). The synthesized catalyst was found highly efficient, retrievable and eco-friendly catalyst for the (ep)oxidation of alkenes and sulfides in excellent yields in a short time. Furthermore, the synthesized nanocatalyst can be reused for four runs without apparent loss of its catalytic activity in the oxidation reaction.
